Companies pay a lot of money to advertise in games. In-game advertising is a big business, and companies are willing to pay big money for ad space. Advertisers understand that gamers are a captive audience, and they're willing to pay to reach them. The cost of in-game advertising depends on a number of factors, including the size of the ad, the game's popularity, and the platform on which the game is played. In general, though, companies can expect to pay tens of thousands of dollars for a single ad.